Post PI buffers........

[Bernardduur]

It works! I lowered the resistors to 22k (approx 1/4 of 100k) and voila, it works like a charm with very sweet sound..... I'm in love!

I use 6L6GC's btw

[Smitty]

Eight Power Tubes

The 820/100R resistive divider IMHO works well with a Super Reverb because the initial feedback voltage is so low. Super is 40 watts into 2 ohms [8.9v=SQRT(40*2)]. The Super divides down about a volt at the tail at rated output.


One of the reasons why the Twin Reverb feels too stiff to so many players is due to the massive increase in negative feedback compared to the Super. Leo used the same 820/100 divider so the voltage feedback goes way up to about two volts at the tail at rated output.

The amp in question has eight output tubes. With the 820/100 there's probably some instability because of too much begative feedback. At 4 ohms 2K7/100 would result in about a volt at the tail and 3K6/100 for 8 ohms.

[Bernardduur]

The 820/100R resistive divider IMHO works well with a Super Reverb because the initial feedback voltage is so low. Super is 40 watts into 2 ohms [8.9v=SQRT(40*2)]. The Super divides down about a volt at the tail at rated output.


One of the reasons why the Twin Reverb feels too stiff to so many players is due to the massive increase in negative feedback compared to the Super. Leo used the same 820/100 divider so the voltage feedback goes way up to about two volts at the tail at rated output.

The amp in question has eight output tubes. With the 820/100 there's probably some instability because of too much begative feedback. At 4 ohms 2K7/100 would result in about a volt at the tail and 3K6/100 for 8 ohms.

Thanks!